Rotary valves rule, OK! - Page 2

mcflux · 05-04-2005, 07:26 PM

Quote:

Originally Posted by outback_ute

There was a rotary-valve head for Holden grey sixes in the fifties built by a guy by the name of Dunstan in South Australia, allowed the Grey motor to see 9000rpm apparently.

How did the bottom end handle this?!?

:

/me pictures an FJ putting an RX7 to shame in the rev stakes...

Psycho Chicken · 05-04-2005, 07:35 PM

So valves are rotated by cylinder pressure, not driven?

Bah, bring on solenoid actuated valves. Much more potential there me thinks.

Perana · 05-04-2005, 07:37 PM

I think so too Psycho... will be much more adjustable than even these rotary valves for flow!

Psycho Chicken · 05-04-2005, 07:47 PM

Yup, can get rid of throttle bodies while we're at it.

Perana · 05-04-2005, 07:53 PM

Yeah will be like Valvetronic but better again!

smciner1 · 05-04-2005, 09:37 PM

Quote:

Originally Posted by outback_ute

There was a rotary-valve head for Holden grey sixes in the fifties built by a guy by the name of Dunstan in South Australia, allowed the Grey motor to see 9000rpm apparently.

Yep, I remember reading the same article years ago. Fitted to a Grey Holen Engined Dragster. Hardly a new idea, but a good idea no less.

shane3 · 06-04-2005, 07:50 PM

Well I like my power to start at 1000RPM and top out around 6000RPM NOT 14,850 RPM. Can you imagine the scream of the engine at that RPM it would be like a 500cc GP 2 stroke with no muffler!, It would have to have a 15 speed auto with a 3000 RPM stall converter.

Steffo · 06-04-2005, 08:16 PM

They never said it peaked power at 14850rpm... just that they managed to rev it that high.

T_Terror · 06-04-2005, 10:10 PM

Quote:

Originally Posted by shane3

Well I like my power to start at 1000RPM and top out around 6000RPM NOT 14,850 RPM. Can you imagine the scream of the engine at that RPM it would be like a 500cc GP 2 stroke with no muffler!, It would have to have a 15 speed auto with a 3000 RPM stall converter.

It would sound like an F1 engine! I want it!

needturbo6 · 07-04-2005, 12:45 AM

i just want one

The MaDDeSTMaN · 07-04-2005, 10:19 AM

Quote:

Originally Posted by outback_ute

There was a rotary-valve head for Holden grey sixes in the fifties built by a guy by the name of Dunstan in South Australia, allowed the Grey motor to see 9000rpm apparently.

Oddly enough I was reading an article about exactly this last night, it was interesting reading, I guess it goes to show that there is still lots of room for improvement on the good-old 4 stroke engine design that we've been using for all these years...

shane3 · 07-04-2005, 11:24 AM

Quote:

Originally Posted by Steffo

They never said it peaked power at 14850rpm... just that they managed to rev it that high.

Please Steffo Read what I wrote, I never said that it's peaked power was at 14850rpm, With revs that high the motor would act like a 2 stroke and would probably not produce 95% of it's power until it was doing over 10,000 RPM,
I do have a question for Steffo, and I'm not having a go at you/him, but have you ridden a high revving 4 stroke motor bike or a 2 stroke? as if you have, you would know that a ZZR250 (learner legal) is a 4 stroke bike and tops out at 12,000 rpm, and will stall at any thing under 3,500 rpm to take off and doesn't produce any real power until the bike is doing at least 7,500 rpm it only produces 26 kW at 12,000rpm, BUT!!!!!! Once you keep up the revs the bike is very quick, 180km/h.
So by the time that you have reached 10,000 RPM on the ZZR250 I'm half way down the road in 3rd laughing.

Steffo · 07-04-2005, 12:07 PM

Ok, but that bike only makes 26kW @ 12,000rpm.. of course its going to be a slow accelerator. What's your point? There are plenty of high revving cars that would leave an FPV GT, HSV GTS, and what have you, for dead in almost any gear. Just because an engine can rev does not mean it will produce 95% of its power at high rpm. Especially with a larger capacity, and 8 cylinders. My uncle's 3.5 V8 Ferrari F355 is an example of that. OK, so it doesn't rev to 14,850rpm, but 8500rpm is pretty high anyway. Peaks power (280kW) at 8250rpm, and torque (363Nm) at 6000rpm. Makes its peak torque when an FPV GT hits the rev limiter, and makes less of it then a Falcon inline-six.

But, 80% of that torque is available from like 2500rpm upwards, it has a very good power/tq curve. So, it accelerates good. Now, Coates give no detail of the power curve of their 5.0 14,850rpm V8, but I imagine it wouldn't be so bad. Not like a 0.25litre motorbike engine anyway.

svo347 · 07-04-2005, 12:14 PM

Interesting comback steffo (Hands Clapping)

Gammaboy · 07-04-2005, 12:16 PM

Dude. a 302 windsor bottom end wouldn't hold together @ 14,500 full stop!

XRQTOR · 07-04-2005, 01:24 PM

Quote:

Originally Posted by Gammaboy

Dude. a 302 windsor bottom end wouldn't hold together @ 14,500 full stop!

He never said a stocker would. A dart block with billet internals should hold to about 12,ooorpm.

Gammaboy · 07-04-2005, 04:48 PM

I never said it was a stocker... If you've ever spun something that does 12,000rpm to 14,500 before, you know theres a big difference between 12 and 14.5 krpm.... and its decidedly unhealthy
5.0 litres breathing through down draft webers turning 14,500rpm? I don't think so.....

shane3 · 07-04-2005, 11:09 PM

Quote:

Originally Posted by Steffo

Ok, but that bike only makes 26kW @ 12,000rpm.. of course its going to be a slow accelerator. What's your point? There are plenty of high revving cars that would leave an FPV GT, HSV GTS, and what have you, for dead in almost any gear. Just because an engine can rev does not mean it will produce 95% of its power at high rpm. Especially with a larger capacity, and 8 cylinders. My uncle's 3.5 V8 Ferrari F355 is an example of that. OK, so it doesn't rev to 14,850rpm, but 8500rpm is pretty high anyway. Peaks power (280kW) at 8250rpm, and torque (363Nm) at 6000rpm. Makes its peak torque when an FPV GT hits the rev limiter, and makes less of it then a Falcon inline-six.

But, 80% of that torque is available from like 2500rpm upwards, it has a very good power/tq curve. So, it accelerates good. Now, Coates give no detail of the power curve of their 5.0 14,850rpm V8, but I imagine it wouldn't be so bad. Not like a 0.25litre motorbike engine anyway.

Your uncle's 3.5 V8 Ferrari F355 is an example of a nice car, but a pic of you with the car would be a nice nail in my coffin, From my experience in life most high revving motors don't produce peak power until they hit there "power band" which is 7/8th of there rev range.